I've recently been porting a Chrome extension to Safari, and encountered this kind of error (bug, feature, etc.)
So, in global page i have a XMLHTTP request to a secure page which is available only after you login.
Example:
- I simply login using browser - as usually you do on facebook or other secure pages
- After that, in global page, I load a login-only-available xmlhttp - and it says i'm not logged in
it seems that global page somewhat has it's own cookies, so a secure page thinks i'm new
ps: in Chrome i can load that page and it thinks i'm acting on behalf of logged in user, so i guess there are some restrictions in Safari
pps: i heard there's a Block third-party cookies option in Safari, but even if i checked it to "Never block" it still doesn't work